There's several different problems that make the odds of the outcome you want very slim. First, let's split your question into pieces.

Part 1 - Widely Received Philosophy Book

What are the chances one can get a philosophy book (in the tradition of continental philosophy) published and delivered to a wide audience if one does not hold any degrees/certificates in philosophy?

Very few philosophy books are widely received in the English speaking world. I gather there's more of a chance of that in France and Spain, but I'm not super well aware of who and what. In other words, philosophy in the English-speaking world rarely amounts to celebrity.

Part 2 - What will philosophers think of it

What are the chances they/their work will be dismissed and not even read or even rejected?

Here, (perhaps mistakenly), I will take this to mean what are the chances philosophers in the English speaking world will find the work serious?

I think the answer is basically nil. Having studied with some of the better respected continental philosophy scholars in the English-speaking world, I can tell you the field for original continental philosophy in English basically does not exist. The number of really famous continental philosophers is quite small (Foucault, Derrida, Deluze, Heidegger, Habermas, Gadamer, Levinas ... ). n.b. Zizek is not really that well-regarded even by continental philosophers.

Moreover, much of their work isn't even respected by most English-speaking philosophers. You can find condemnations of it as junk through the internet.

A second aspect is that you're probably going to not even get to full peer review without some formal training in philosophy. (What do I mean by full peer review? See all of these). Most likely, you'd get desk-rejected by the editor when they read you abstract. The reason is that (regardless of its virtues and demerits) if you're self-studied, you won't be used to the normal styles of philosophical writing.

Part 3 - Writing Success

Can you be a successful writer if you do not hold a degree in philosophy but are passionate enough to write a book and you are an avid philosophy reader?

If we separate this from "widely received" and "accepted by the philosophical community", then I think if you write in the right way and in a certain popular style, you could potentially write something (not specifically considered academic philosophy) that gets well-read enough for you to have a career, but you'd really have to ask writers.SE or some other context.

Part 4 - WHY?

Simply put, there's no money in academic philosophy and little fame to go around. Few outside of philosophy read contemporary philosophers. And usually they-1 are reading this because they-1 too are contemporary philosophers or work in a cognate field (law, cognitive science, psychology, social sciences).

For academic publications, you generally get a free copy of the book and no money. A good print run is measured in the thousands of volumes. Tens of thousands is huge.